PURPOSE: The authors retrospectively evaluated the safety and effectiveness of percutaneous radiofrequency ablation of lung tumors close to the heart or aorta. MATERIALS AND METHODS: Forty-two tumors (mean diameter, 25 mm +/- 16; range, 5-73 mm) located less than 10 mm from the heart or aorta were treated with radiofrequency ablation in 47 sessions. Lung tumors were classified into two groups according to their distance from the heart or aorta: group A (n = 27) comprised tumors at a distance of 1-9 mm; group B (n = 15) comprised contiguous tumors (distance, 0 mm). The safety and technique effectiveness of the procedure, defined as no evidence of local tumor progression, were evaluated. RESULTS: Radiofrequency ablation was feasible for all the 42 tumors. Procedural complications included asymptomatic pleural effusion (n = 5), small pneumothorax (n = 11), pneumothorax that necessitated chest tube placement (n = 4), and lung abscess (n = 1). No complications related to the specific tumor location, such as the accidental insertion of the electrode into the heart or aorta, pericardial effusion, arrhythmia, or cardiac infarction, occurred. The overall primary technique effectiveness rate was 75.8%, 45.9%, and 45.9% at 6, 12, and 24 months, respectively. This rate in group A (94.7%, 69.3%, and 69.3% at 6, 12, and 24 months, respectively) was significantly (P < .001) higher than that in group B (42.9% and 8.6% at 6 and 12 months, respectively). CONCLUSIONS: Radiofrequency ablation of lung tumors close to the heart or aorta was safely performed. The local control of tumors contiguous to the heart or aorta was considerably lower compared with the tumors that were close but not contiguous to these structures.